There exists a typical technique for capturing data transmitted on a communication path and measuring the traffic of captured data.
In some cases, a communication service provider charges users on an as-used basis. For example, accounting data obtained by measurement performed on a user's terminal is transmitted to a server of a service provider, and data of the user's terminal is updated on the basis of the accounting data in the server.
A technique for setting a capturing start time and a capturing end time and intermittently performing capturing from the capturing start time by receiving packets at every capturing cycle having a capturing width and a technique for acquiring packets mirrored from packets flowing in each client-server segment or each server-server segment are provided.